Sensory signals from within the body modulate the physiological and behavioral responses of animals to their environments. Though these interoceptive signals often do not reach conscious awareness, they can have a powerful impact on the motivation and emotional learning of animals placed in different environmental contexts. However, the insights gained so far into the operation of these pathways stem mainly from observation and manipulation of adults, and cannot be generalized to developing animals. The natural process of neural development offers special opportunities to probe the functional organization of interoceptive pathways. The proposed research will address the postnatal ontogeny of central neural pathways that link interoceptive components of the brainstem, hypothalamus, and limbic forebrain in normal and pathological conditions. The proposed research will directly examine functional relationships among interoceptive pathways during normal and abnormal development, filling a major gap in the present literature. The experimental outcomes will significantly enhance our understanding of how these pathways mature, and how they operate in health and disease. [unreadable] [unreadable] [unreadable]